In various areas of the world, navigational lights are required for vessels, the requirements of which may depend on the size of the vessel. The requirements of navigational lights typically apply between sunset and sunrise or in low visibility conditions. For example, the United States Coast Guard requires power-driven vessels less than 39.4 feet in length to display red and green sidelights visible from a distance of at least one mile away on a dark clear night. Unpowered vessels less than 23 feet long exhibit the same lights as for powered vehicles less than 39.4 feet in length, if practical. Various other lighting requirements for vessels may be applicable, depending on the location.